Steam line water relief valve



Feb. 25, 1936. L. c. HYATT 2,031,953

STEAM LINE WATER RELIEF VALVE Filed Jan. 22, 1952 INVENTOR- Zomls Hyaft Patented Feb. 25, 1936 STEAM LINE WATER RELIEF VALVE Louis 0. Hyatt, Albany, N. Y., assignor to Consolidated Car-Heating Company, Inc., Albany, N. Y., a corporation of New York Application January 22, 1932, Serial No. 588,219.

8 Claims.

For-a detailed description of the present form of'myinvention, reference may be had to the following specification and to the accompanying drawing forming a part thereof, wherein Figs. 1 'to .6 are explanatory diagrams;

Fig. is a vertical transverse section, and

Fig. '8 is a plan, half in section, on the line 16-1; of Fig. 7

Figs. 9 shows the device in full on a train-line 10 couplerof the Gold type which had formerly contained an ordinary gravity trap.

It is the purpose of my invention to supersede the present practice of clearing a train line of water, formed by condensation of steam therein,

by blowing off the train line at the rear end of the train; or by leaving the said rear end of the train line partially open. This present practice does not remove the condensate from the line until after it has caused pressure drop. The condensate accumulates all along the steam train line and the entire accumulation has to flow to the rear of the train line, in the said practice, in order to escape at the rear end. Thus each section of the train line has to handle, not only ;;its own condensation, but also the accumulation in all sections ahead of it. Thereby the effective steam area'of the train line becomes smaller and smaller because of this accumulation of condensate therein.

30 I provide by my invention a trap that may be placed at intervals along the train line at any convenient low point or points-as at the depending couplerswhich keeps the entire length of the train line completely and locally free of pondensation water. My trap acts at frequent intervals in response to any local accumulation of condensation therein.

This trap, shown in section in Fig. 7, consists of a hollow bowl or casting A provided with a 40 lateral neck B which may be screwed into an ordinary train line coupler with the customary screen C. In Fig. 9 is shown a coupler of the usual Gold type joining depending length of hose from which the regular gravity trap has been removed and my new trap substituted therefor. The top of said casting A is closed by a screw cap D-with the usual gasket at the joint. To the inside of cap D is secured the rear end of a corrugated metal bellows E which carries at its 50 lower end a conical valve F which is adapted, by the expansion of the bellows, to seat in and close the central passage in anannular bushing G forming the valve seat. Outside of valve seat G a cover plate or shut-off nut H is screwed to the 55 outside of the bowl or-casting A. It is perforated with two holes, to permit the escape of the condensate, and between the holes is a conical valve seat K which, when the nut H is screwed up tight, will close the outlet of the valve seat G. Normally, of course, the nut H is not screwed up tight but left open, as shown. This shut-off nut H is shown as controlled by a seal I, since it is only in an emergency that the nut H will be screwed up tight as aforesaid.

The foregoing being a description of my device, I will now explain the principle of its operation.

First, it is important to consider the mode of filling the aforesaid bellows E and the action of its associated parts. Referring to diagrammatic Fig. 1, the distance L represents the natural free length of the empty, unsealed bellows. By compressing the bellows, between thumb and finger, so that the corrugations touch one another, its

length becomes L minus a fraction of an inch, as

appears in Fig. 2. When allowed to re-expand, its length will again return to L because of the release of the compression stress in the bellows wall. If the empty bellows of Fig. 1 is subjected to tension, instead of compression, by pulling its top and bottom apart, the bellows can be extended to a length L plus a fraction of an inch, as appears in Fig. 3.

If new the bellows is compressed, as in Fig. 2, and, while so compressed it is filled with water and the opening in the top of the bellows is sealed with solder, it will not return as before, on the release of pressure, to its normal free length L, but will remain at the compressed length, L minus a fraction of an inch, as appears in Fig. 4. That is because, while its natural resiliency would tend to expand it to its normal length L there is a. greater external force (atmospheric pressure) which keeps it compressed. It is true that by exerting on the sealed waterfilled bellows of Fig. 4 a sufficient expanding pressure, without changing its temperature, it could be drawn out to a length L, or an even greater length, but the moment such artificial expansion was released, the bellows would return to its normal length, viz., L minus a fraction of an inch, as shown in Fig. 4. Such artificial expansion would not change the amount of water in the bellows. Its return to normal would be due to atmospheric pressure tending to cancel the vacuum caused inside it by its artificial expansion aforesaid. So the normal length of the waterfilled, sealed bellows at atmospheric pressure is L minus a fraction of an inch. Such is its length in the normal condition of the trap, which is shown in Fig. 5, also in Fig. 7 which represents the detached trap. If the bellows is not compressed, and then sealed being full of water when so compressed, it is not properly prepared. The valve F is now open, as in Figs. 5 and 7, and any water which may be in the train-line flows by gravity to the low points of the train-line, such as that at which the trap is located, and is drained off by the open valve. Thus the traps locally drain the entire pipe when no steam is on the line.

But the moment steam enters the line it comes into contact with the contracted bellows E. The steam heat is transferred to the water within the bellows and generates steam therein. Thistranse fer of heat continues until the contents of the bellows reaches the same temperature as the steam surrounding it. The pressure on the bellows is then the same, both inside and outside,

because the pressure of saturated steam depends on its temperature. In consequence the aforesaid compression stress, which' was put on the walls of the bellows when it was compressed and filled and sealed, is now unopposed and is free to react. It therefore causes the bellows to expand to its full length, as shown in Fig. 6.

This change from'the normal length ofthe bellowsi. 'e.L minus a fraction of an inch, as in Fig. 4to its natural free length L, is more than enough to seat the valve F against valve seat G. In'pr'actice the movement of the valve is only .170 inch from fully open to fully closed position;

Now so long as steam alone surrounds the bellows, the contents of the bellows will be at the same temperature as the temperature of the steam outside of it; the inside and outside pressures will be equal and the valve F will remain closed, due to the spring action of the bellows wall. Steam cannot then escape from the trainline.

But when even a small amount of condensate in, because the volume of steam inside the bellows is limited. But outside the bellows the steam line pressure remains practically unchanged, being maintained by the locomotive boiler. Whatever condensate there may be in the trap outside of and around the bellows is not enough to appreciably affect the train line pressure; In consequence the train-line pressure'lifts the conical Valve F from its seat and allows the condensate to flow out. When the condensate has thus been removed the steam pressure will equalize inside and outside of the bellows and the resiliency of the bellows wall will again close the valve.

This device has but one moving part, viz., the bellows. This bellows is normally contracted and the pipe is therefore automatically drained when there is no steam on the line. Dry steam at any pressure will expand the bellows and close thetrain pipe. But even a teaspoonful of condensate, in the steam that is present, around it will cause the bellows to contract proportionately to the amount of condensation andthus open the valve. As soon as the condensate is removed by this opening of the valve the steam will again expand the bellows and reclose the outlet. So sensitive is the bellows to the presence of condensate,

that a person not familiar with my device mightv think the valve was leaking. Such an impresthan teaspoonful amounts. sity of the train or yard crew blowing out steam train linesiat the rear end of the train and avoids sion is more apparent as the steam pressure gets higher. Under normal conditions condensation is continually accumulating in a steam pipe line, therefore a proper relief valve should continually allow condensate to escape. The fact that the escaped condensate immediately changes to steam in the atmosphere does not prove that anything but the condensate is escaping. To prevent all action of condensate on the valve it may be unscrewed quickly and turned upside down, when the bellows will be momentarily free of condensate and will then close and hold steam tight. It will reopen as soon as enough condensate collects to reach the bellows and cause it to open.

This device, by keeping the entire pipe line free of condensate, reduces the pipe line pressure previously required to force steam through a clogged pipe line. It permits. maximum steam flow with a much lower steam pressure.

The device is simple and inexpensive. It requiresno adjustment, it discharges only conden sate, and discharges it as rapidly as it is produced and at distributed points along the line in less It avoids the necesall' occasion for bleeding the rear'end of the train line by keeping it slightly open with a con tinual loss of steam.

What I claim as new and desire to secure by Letters Patent is:

1. In a' condensate relief valve, an expansible and contractible vessel, and a thermally respon sive liquid therein, said liquid having a boiling temperature approximately the same as that of the condensate to be controlled, the volume of said liquid being such that unvaporized liquid fills the vessel while said vessel is contracted, so

said vessel will balance while the vessel is surrounded by vapor, said vessel being so constructed and arranged that it will expand to its limit that the internal and external pressures upon while said pressures are balanced and will contract while said pressures are unbalanced.

2. In a condensate relief valve, a closed vessel consisting of end walls connected by an expansible and contractible body portion capable of storing expansible energy while contracted, said vessel containing water, so as to have approximately the same boiling point as the condensate, the volume of said liquid being approximately equal to the internal volume of the vessel while collapsed to its minimum volume, so that at normal temperature of steam surrounding said vessel the internal pressure is balanced by the external pressure produced by said steam. V

3. In a condensate relief valve, a closed longitudinally expansible and contractible vessel capable of storing expansible energy while contracted, said vessel containing water, the volume I of water being such that it is approximately equal to" the internal volume of the vessel while collapsed to its minimum degree, so that at normal temperature of steam surrounding said vessel the internal pressure is balanced by the external pressure produced by said steam.

4. In a condensate relief valve, an expansible I and contractible vessel formed with corrugated walls,and a thermally responsive liquid therein, said liquid having approximately the same boiling temperature as the condensate, the volume of said liquid being the same as the volume of said vessel while it is contracted to its minimum volume, so that the internal and external pressure upon said vessel will balance while the vessel is surrounded by vapor, the corrugations of said vessel being so constructed and arranged as to cause the vessel to expand to its limit while said pressures are balanced and to contract while said pressures are unbalanced, the limit of contraction being controlled by the corrugations.

5. In a condensate relief valve, a hermetically sealed corrugated casing constructed and arranged to expand and contract axially, said casing being capable of storing expansible energy while contracted, a thermally responsive liquid in said casing, said liquid having approximately the same boiling temperature as the condensate, the volume of liquid being approximately equal to the internal volume of the vessel while collapsed to its minimum volume, so that at the normal temperature of steam surrounding said vessel the internal pressure is balanced by the external pressure produced by the steam, support means connected to one end wall of said vessel, and a valve carried by the other end wall of said vessel.

6. In a condensate relief valve, an expansible and contractible velve member capable of storing expansible energy while contracted, a thermally responsive liquid within said valve member, said liquid being of approximately the same boiling point as the condensate, the volume of the liquid being equal to the capacity of the valve member while so contracted, so that the pressure of said liquid will balance the external pressure on the valve member at a predetermined temperature and thereby freeing it for expansible movement under said stored energy.

7. A condensate relief valve comprising 2. casing having an inlet opening and an outlet opening, a removable top plate for said casing, a longitudinally expansible and contractible vessel located within said casing and having one end attached to said top plate and a valve on the other end positioned to control said outlet opening, and a thermally responsive liquid within said vessel of the same boiling point as the condensate, the volume of said liquid being equal to the internal volume of the vessel while contracted to its minimum length so that any internal pressure developed in the vessel will be balanced by the external pressure applied by the surrounding vapor within said casing, said vessel being so constructed and arranged as to expand from its contracted state while said pressures are balanced.

8. A condensate relief valve comprising 2. casing having an inlet and an outlet, a sealed expansible and contractible vessel in said casing carrying a valve controlling the outlet, means supporting said vessel so that it will seat the valve while the vessel is expanded to its normal free length, and a vaporizable liquid within said vessel, the volume of which is equal to the volume of said vessel while contracted from its normal free length to valve unseating position, the boiling point of said liquid being approximately the same as that of the condensate to be controlled by the valve, so that the internal pressure created by said liquid Will balance the external pressure on said vessel while it is surrounded by vapor, the wall of said vessel being elastic so that it will expand by its own resilience to valve closing position while the pressures are balanced.

. LOUIS C. HYA'I'I'. 

